The hypoglycemic effects of 2 mushrooms, Pleurotus ostreatus and Lentinus edodes, on streptozotocin(STZ) induced diabetic rats were investigated in this study . Diabets mellitus was induced in male Sprague-Dawley rats by the injection of STZinto the tail vein at a dose of 45mg/kg. Sprague-Dawley male rats(200-250g) were assigned to one control and three STZ-diabetic groups. Diabetic groups were assigned to STZ-control, pleurotus ostreatus and Lenitinus edodes groups. All groups were fed a AIN 76 diet. The two experimental groups were fed with each protein-bound polysaccharide(150mg/kg BW) for 14 days and with carboxymethyl cellulose for STZ-control group. The body weight gain was monitored and the blood levels of glucose and cholesterol were measured . Levels of protein triglyceride, and free fatty acid in plasma were analysed. Serum aminotransferase activity as also measured. The body weight gain was lower in the all diabetic groups than in the of normal group. The weight of spleen was reduced by adminstration of the Lentinus edodes protein-bound polysaccharides. The result suggest that orally administered Lentinus edodes protein-bound polysaccharides exhibited hypoglycemic effect in STZ -induced diabetic rats and that these protein-bound polysaccharides may be useful for the management of diabetes mellitus.